Norwegian research scientists are now working on the concept of storing electricity at the bottom of the sea. The energy will be stored with the help of high water pressure. It’s a new idea invented by a German engineer who has spent much of his professional life working in aerospace technology.

Rainer Schramm, inventor and founder of the company Subhydro AS said, “Imagine opening a hatch in a submarine under water. The water will flow into the submarine with enormous force. It is precisely this energy potential we want to utilize. Many people have launched the idea of storing energy by exploiting the pressure at the seabed, but we are the first in the world to apply a specific patent-pending technology to make this possible.”

Subsea Energy Storage Block Diagram. Click image for more info.

Subsea Energy Storage Block Diagram. Click image for more info.

Schramm has joined forces with SINTEF, the largest independent research organization in Scandinavia to research the concept. “SINTEF has experts in the fields of energy generation, materials technology and not least offshore and deep-water technology, which means we have all the expertise we need in one place,” he said.

To use the water pressure at the seabed in practice, the mechanical energy is converted by a reversible pump turbine, as in a normal pumped storage hydroelectric plant.

Schramm explains, “A pumped storage power plant is a hydroelectric plant that can be “charged” up again by pumping the water back to the upper reservoir once it has passed through a turbine. This type of power plant is used as a “battery”, when connected to the power grid.”

In this pumped storage power plant a turbine will be connected to a tank on the seabed at a depth of 400-800 meters. The turbine is fitted with a valve, and when this is opened, water flows in and starts turning the turbine. The turbine drives a generator to produce electricity. One can connect as many tanks as one might wish. In other words, it is the number of water tanks that decides how long the plant can generate electricity, before the energy storage capacity is exhausted.

“When the water tanks are full, the water must be removed from the tanks,” Schramm explains. This is achieved by running the turbine in reverse, so that it functions as a pump. The process consumes energy from the power grid, just as when one charges an ordinary battery. Although a bit more energy is used to empty the water tanks than can be recovered from flooding them, the degree of efficiency of this type of power plant is just as high as that of a conventional, onshore plant. According to Schramm, calculations indicate an electric storage efficiency of approximately 80% per power emptying cycle.

Another advantage of the system is that equipment can be scaled according to users’ requirements, both as regards the turbine size and the number of water tanks. A plant of normal size will produce roughly 300 megawatts for a period of 7-8 hours. This is enough energy to supply just over 200,000 (British measure) households with electricity for the same time.

Schramm said, “We envisage that this type of storage plant will function well in conjunction with, for example, wind farms. At strong wind conditions, excess electricity is sent subsea to pump water out of the storage tanks. In periods with little wind, energy can be obtained from this underwater plant instead. The same applies to solar generation: the pumped storage power station can contribute to constant electricity production at night time when there is no sunshine to run a solar power plant.”

In addition to the number of tanks, the sea depth also determines the effectiveness of the plant: the deeper the equipment is located, the greater is the pressure difference between the sea surface and the seabed, and the more energy is stored in a single tank.

Schramm explained, “This is part of the reason why we want to try out the technology in Norway.” In his native country Germany the sea is too shallow for the system to be profitable, but there are many parts of the world where great water depths are located close inshore, such as the marine areas around Italy, Portugal and Spain, as well as North and South America.

This where SINTEF comes in. One of the challenges is to develop a type of concrete that can be used to cast the water tanks, which are placed on the seabed. Tor Arne Martius-Hammer at SINTEF Building and Infrastructure is an expert on strong, light concrete types.

Martius-Hammer explains the SINTEF work with, “The challenge is to find the optimal balance between strength and cost. If we achieve the goal of creating a concrete that will withstand at least 5 times as high loading as ordinary concrete, we can reduce the wall thickness by 75%. This is a critical factor. We need to reach production and installation costs which make storage of energy economical in relation to the price of electrical energy. One of the solutions SINTEF will work on is reinforcing the concrete with thin steel fibers instead of the normal steel rebar. This will result in a significant simplification of the production process. Concrete is in existence at present which can be used, but our job is to develop a cheaper alternative.”

It all seems elegantly simple to use gravity and pressure to achieve high energy storage efficiency. As the team in Scandinavia is figuring out, its much more of an engineering exercise of the extreme.

Eighty percent efficiency look quite attractive. No battery, chemistry problems, or life cycle issues other than wear and tear. The concrete tanks could last indefinably. The physics are quite simple with no problems such as compressing air that would loss energy to thermal loses. One simply needs to be near a deep body of water.

Lets hope the thin steel fibers replacing the normal steel rebar work out great.


24 Comments so far

  1. Jagdish on May 16, 2013 3:40 AM

    Storing energy as compressed air in underwater balloons/bladders could be even simpler and cost=effective. The pressure of inside air would be the same as that of sea-water with minor stresses in the bladder. compression can be entirely mechanical, saving on electrical parts. The energy could be used:-
    a. As compressed air with pneumatic motors.
    b. to drive a wind turbines at surface level.
    c. converted to electric power with a turbine/generator.
    A good idea for wind power.

  2. Graham on May 16, 2013 10:48 AM

    No mention of cost of corrosion, or maintenance at great depth. What next? Will someone invent the water tower instead? I agree with Jagdish.

  3. hsin on May 17, 2013 6:32 PM

    Hm, for few years im bearing some idea, having no time to educate about if it is possible (or to ask somewhere).
    Maybe someone here could tell me something …
    The idea is:
    – why not produce some gas under ocean for similar purposes as in the commented article.
    E.g. some cheapest chemical reaction producing hydrogen or oxygen, could slowly accumulate amounts allowing to use underwater pressure …

    Eg. a simple sphere with one small hole at bottom, filled with ocean water, could slowly fill with produced gas, that pushes watter out (hmm would the high pressure make water to absorb gas easier than in low-pressure cases (e.g. it is easy to make bubbles of air in bottle or in swimming pool ..

    Thanks for any answer.

  4. george ivanus on June 7, 2013 4:02 AM

    it is an excellent idea .
    with an adjustable pressure mechanism that regulate the flow it can be a very efficient method of e.s..

    now, what would you say of this STEP FORWARD:

    obtaining energy from Oceans by converting the HIGH Pressures (gravity result) from the DEEPS into electric energy .

    it uses a vertical CONVEYER type MECHANISM (s. BUCKET CONVEYER). Instead of buckets , the conveyer has PISTON/CYLINDERS attached to it (a piston in a piston shirt) filled with Pre compressed gas (oxygen , nitrogen ,etc.).

    the weight of the P/C is 10% higher then displaced vol. of water (negative buoyancy – Arhimede principle) to allow easy sinking. in order to obtain that ,must use thick steel walls ( 5 inches thick!)

    the conveyer is 15 000 feet (4500 meters – hydrostatic pressure=460bar) long so the P/C are SLOWLY SUNK (0.5 miles/hour) to this depth in order to allow equaling of pressures (internal-external)in a ADIABATIC compression. this is the DESCENDING RACE of the unblocked P/C.

    at the LOWER END of the conveyer ( internal pressure is close to 300 BAR) the P/C is blocked in the compressed position and follows the ASCENDENT RACE to SURFACE ( storing this POTENTIAL ENERGY all the way up).

    the SURFACE infrastructure is composed by a water PUMP and FRANCIS TURBINE ( similar to a hydropower plant).

    at the return to surface the potential energy stored as compressed air is transformed into KINETIC ENERGY thru mechanical work in a ADIABATIC process .
    the P/C actions the Water PUMP – Turbine .

    my calculation shows a installed power of 1000 MW (24/24, 365/365) for a 10 000 feet long , 3000 cubic feet P/C , 1200 P/C per conveyer (120,000 TON per facility ).
    my calculation result in a EROEI of 31-75 for 15000 feet s.
    but an expert opinion is required here.

    thank you,
    best regards,
    Ivanus George

  5. mk on October 29, 2013 6:53 AM

    I am not an expert but ur idea is promising. I am working on slight modification of your idea.

  6. mk on October 29, 2013 6:54 AM

    Can u send me ur calculations?

  7. george on October 29, 2013 7:57 AM

    introduce yourself!

  8. mk on October 29, 2013 3:50 PM

    mail ur email id.

  9. zvibenyosef on October 31, 2013 11:43 AM

    For a 15000 foot conveyer, it will take 6 hours to lower the P/C. It will probably take the same amount of time to raise it. But raising it will require energy, since the weight is 10% higher then displaced vol. of water.
    So the power production will be intermittent, with lengthy breaks during which time the P/C must be lowered and raised, and input of energy during the raising phase.

  10. george on October 31, 2013 12:51 PM

    it is a conveyer mechanism : it has 2500 P/C , a displacement of 35000 ton , it uses 31000 tons of medium grade steel .
    the 2500 P/C assure a rather continuous input of energy (my opinion).

  11. george on October 31, 2013 1:04 PM

    and correct,
    it will weight 3000 ton more on the asc. race.
    a rugged compute:

    necessary input P= 30,000,000 Newton x 0.1 meter/second x 1.1 (f. coefficient) = 3.5 Mwatt

    the average output mechanical P for the 60 seconds = 112 Mwatt.
    result an electrical P = 80-85 Mwatt

    i.e. EROEI= 20-25

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  13. Rick Dickson on June 28, 2014 10:10 AM

    Far from a new idea. This is basically a rip-off of a patent pending invention I developed in 2006. It is widely promulgated on the internet as “Ocean Pressure Electric Conversion”. I have a similar spherical water pressure device called the “hydrosphere.” Just do a Google search under that description or under Richard Dickson inventor. More information is available on PES WIKI (Pure Energy Systems), Beyond Fossil, and Ten Innovations in Hydropower on the net. This engineer apparently saw my work on the internet or may have got the idea from a German engineering firm I contacted about it years ago. Anyway, good luck with the invention.

  14. Rick Dickson on June 28, 2014 10:46 AM

    I am a nationally recognized US renewal energy inventor, and contacted Howaldsdeutschewerke, the German shipbuilding company about this concept in 2004. The idea was to use it as a new form of submarine propulsion. I also have been promulgating the Ocean Pressure Electric Conversion idea on the internet for years. In fact I invented the acronym, OPEC, for it and even had an extensive Wikipedia article on it at one time (since migrated to a “Hippie” WIKI article). I also had a website on the internet from 2007-2008 with animation showing how the Ocean Pressure concept worked using hollow spheres to store the water pressure. In 2006, I won a History Channel “Invent Now” contest award for the concept. Obviously, this is theft of my intellectual property, but without a granted US patent, I had no chance to control it, as the patent office rejected the original invention. I am amazed that this engineer got a patent on the device in Germany when my similar invention was so widely promulgated on the internet. I suspect the patent would not survive a legal challenge though by anyone. Over the years from 2004-through now, I have contacted the media, universities, and even the Nobel Foundation. No one has shown interest until now in funding or pursuing the idea. Read more at these links:

    Interestingly, this is not the first time my renewable energy ideas have been “borrowed”. Cornell University researchers “borrowed” my “Wind Tree” concept first promulgated in my self-published book, “New Concepts in Renewable Energy.” They did subsequent research that confirmed the validity of my original research and concept on this new idea to bring piezoelectric wind power into suburban and urban areas using piezoelectric artificial “leaves” linked in series on artificial trees around buildings and other structures. After a prolonged fight for attribution, I managed to get Cornell’s ethics committee to give me proper attribution on their website. However, recently, they took down their website online. Still they did give me minor attribution in a paper they wrote for SMASIS (Society of Mechanical Engineers)about the concept.

  15. george on June 28, 2014 10:55 AM

    doesn’t matter who’s was the idea.
    the point is : DOES IT WORK?

  16. Rick Dickson on July 12, 2014 10:10 AM


    It works. I have tested it on a very small scale in a very deep lake in Oregon. The problem is the big energy companies don’t want it. It would result in cheap, hydroelectric power production worldwide, as any country with access to oceans or deep lakes could harvest cheap, 24/7 hydropower. You must also remember that energy is one key component of national power. Despite what the major countries around the world say about helping less developed nations, they still want to largely control the energy supply. Now if energy were more universally available and cheap that would diminish the power of the major countries. Hence, another reason this invention will probably never see the light of day.

  17. Rick Dickson on October 8, 2014 10:17 PM

    I emailed the Norwegian Hydroelectric Society details concerning my Ocean Pressure Electric Conversion technology years ago. You can also read more about it my book on (Kindle)-New Concepts in Renewable Energy:

  18. george on October 9, 2014 2:34 AM

    Rick ,
    I am sorry that others stole your ideas .
    as to me I wouldn’t mind if someone do that to me as long they do something with it .
    the shame is that some good ideas are neglected .
    i saw some good ideas on using OPECs , some more refined then mine and i am glad you managed to put it in practice .
    can we find a separate route to finance/build a larger scale model , without the help of ‘pained in the ass’ big shots ?

  19. kiprono on January 9, 2015 2:41 PM

    this amazing….just when i thought i was the only1 working on the use of liquid filled cylinder attached to belt for continuos harvest of intense ocean pressure….i was wrong but the idea is convicingly valid.

  20. Mani on January 28, 2016 12:20 AM

    Can anyone think of using the buoyant property of the water in advantage of emptying the tanks.

  21. Mani on January 28, 2016 12:27 AM

    How about a buoyant material being released from inside the pressure sealed container to bring the tanks upward to the normal air pressure water inside can be easily drained out and can be dropped back again with heavy weights attached.

  22. jerome on April 13, 2016 8:42 PM

    It doesn’t matter who is the first inventor to think of the concept ,you’ve published your invention first so i think you’ve earned your credit. If you are telling us all your stuffs to earn money whenever somebody want to ‘borrow’ your concept that might be a hard talk. What we want in this critique box are suggestions to improve the project.

  23. Dave Taggart on June 20, 2016 4:47 PM

    This idea has rattled around in my brain since my first years on a submarine last century. The real question is who has the financial capability to research, develop, engineer and produce the concept. Its certainly sensible and feasible in my opinion but is it practical and economical, “profitable”
    Hope to see it happen.

  24. Anar on April 17, 2017 6:10 AM


    Here I see that some guys criticize others with stealing their idea.
    I personally came up with this idea without seeing it in any book or website. I came across to the same idea in your website while searching for this concept.
    To me, it is just common sense. Anybody (1 in 100 or at least 1 in 1000 people) can come up with a similar idea. I wish good luck to the person who will realize the idea.


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